An inpatient program with selected overnight stays, for childhood and adolescent neuropsychiatric disorders is ongoing. The condition currently under study is that of hyperactive children (HAC). Pharmacological compounds under study in these disorders include methylphenidate, amphetamine, piribedil, L-DOPA, tryptophan, Mianserin, clorgyline, and desipramine. Piridebil is safe but clinically ineffective in HAC while L-DOPA is minimally clinically effective. Tryptophan is effective on attention measures. Pharmacokinetic studies with clinical responses are included. Amphetamine half-life in children is about one-third that of adults. Behavior and motor activity responses to d-amphetamine occur during the absorption phase as determined by serial plasma amphetamine following a single dose. Central neurotransmitters and their metabolites are being studied in plasma and urine. Urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) shows a time-related decrease during treatment with d-amphetamine; dopamine metabolites are unchanged. Tyramine and its metabolites are also decreased following d-amphetamine, whereas phenylethylamine is greatly increased following d-amphetamine.